7β,8β-Epoxycardenolide glycosides of Asclepias eriocarpa

Cheung, H. T. Andrew; Watson, T. R.; Seiber, James N.; Nelson, C. J.

doi:10.1039/p19800002169

Cited by 24 publications

(8 citation statements)

References 1 publication

(1 reference statement)

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“…Since the pioneering work of Brower, Reichstein, Rothschild, and their colleagues that described cardenolide sequestration by the mon arch, more recent work in the laboratories of Brower in Florida and Seiber in California explains much of the ecological and evolutionary rel evance of cardenolide sequestration in this specialist herbivore (Seiber et al, , 1983(Seiber et al, , 1984Brower et al, 1982Brower et al, , 1984aBrower et al, ,b, 1988Brower, 1984;Brower and Fink, 1985;Cohen, 1985;Cheung et al, 1988;Malcolm et al, , 1991Malcolm, 1990). and Nelson (1991a,b) summarized much of this work.…”

Section: Monarch Butterfly (D Plexippus)mentioning

confidence: 99%

Cardenolide-Mediated Interactions between Plants and Herbivores

Malcolm¹

1991

Herbivores: Their Interactions With Secondary Plant Metabolites

154

180

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Section: Monarch Butterfly (D Plexippus)mentioning

confidence: 99%

Cardenolide-Mediated Interactions between Plants and Herbivores

Malcolm¹

1991

Herbivores: Their Interactions With Secondary Plant Metabolites

154

180

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“…1) Asclepias species are known to contain many kinds of cardenolides and their glycosides. [2][3][4][5][6][7][8][9] A. syriaca has also been reported to contain these compounds. [10][11][12] We have previously studied cardenolides and their glycosides.…”

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confidence: 99%

Acylated-Oxypregnane Glycosides from the Roots of Asclepias syriaca

Warashina

Noro

2009

CHEMICAL & PHARMACEUTICAL BULLETIN

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177Asclepias syriaca L. is a plant indigenous to North America and distributed widely. The monarch butterfly (Danaus plexippus L.) feeds on the Asclepias genus for protection from vertebrate predators. 1) Asclepias species are known to contain many kinds of cardenolides and their glycosides. 2-9)A. syriaca has also been reported to contain these compounds. [10][11][12] We have previously studied cardenolides and their glycosides.13) But, until now, there have been no reports about pregnane glycosides from A. syriaca. Pregnane glycosides are considered characteristic of Asclepias species.14-18) Accordingly, we started an investigation of pregnane glycosides and found twenty new 12-O-acylated-oxypregnane glycosides in the roots of A. syriaca. The present paper describes the isolation and structural determination of these new pregnane glycosides.A MeOH extract from the dried roots of A. syriaca was suspended in water. The suspension was extracted with diethyl ether and partitioned into an ether-soluble fraction, a water-soluble fraction and an ether-water emulsified fraction. The residues of these fractions were chromatographed on a silica gel column to give fractions of acylated-oxypregnane glycosides from which twenty new compounds were obtained along with seven known compounds. The structural determination of the known compounds 7, 10, 12, 13, 18, 23, and 27 was made based on comparisons of NMR spectral data with data in the literature. 16,17,19) In order to acquire the component aglycones and sugars, the fraction containing pregnane glycosides from the silica gel column chromatography was subjected to acid hydrolysis. The afforded aglycones were identified as ikemagenin (1a), 19,20) 5a,6-dihydroikemagenin (20a), 17) and 12-Otigloylisolineolon (21a), 17) in view of the 1 H-and 13 C-NMR spectral data.The acquired sugar mixtures were fractionated to cymarose, oleandrose, digitoxose, and canarose using silica gel column chromatography. The absolute configurations of these sugars were believed to be D-forms on the basis of the optical rotation values.Compound 1 was suggested to have the molecular formula Thus, 1 was glycosylated at the C-3 position, and was considered to be ikemagenin 3-O-diglycoside. Moreover, acid hydrolysis of 1 showed that the sugar moiety consisted of digitoxose and oleandrose, and these sugars were identified as b-D-digitoxopyranose and b-D-oleandropyranose, as judged from the J values of each anomeric proton signal (Jϭ9.5, 2.5 Hz). The sequence of the sugar moiety was determined from measurements of the rotating frame nuclear Overhauser effect (ROE) difference spectra irradiating at the anomeric proton of each sugar in 1. ROEs were found between Acylated-Oxypregnane Glycosides from the Roots of Asclepias syriacaTsutomu WARASHINA* and Tadataka NORO Institute for Environmental Sciences, University of Shizuoka; 52-1 Yada, Suruga-ku, Shizuoka 422-8526, Japan. Received October 29, 2008; accepted November 25, 2008; published online November 26, 2008 Twenty new pregnane glycosides were obtained...

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“…Whereas 2 17 and 3 18 could easily be recognized as well-known compounds by comparison of the 1 H and 13 C chemical shift data, structure 1 seemed to be unexpected since the NMR spectra showed peaks typical of a methoxy group with singlet at υ H D 3.35 (3H) and υ C D 54.6 and for an acetal CH with singlet at υ H D 4.88 and υ C D 101.3. No further peaks appeared indicating that a sugar moiety was present; therefore, we had to conclude that the acetal carbon is a member of the steroidal skeleton.…”

Section: Resultsmentioning

confidence: 89%